Download The Biosphere

Ecology and Our Ecosystem
Characteristics of the Biosphere
• Ecology is the study of
organisms and their
interactions with the
environment. (eco-home)
• The biosphere is the lifesupporting region of the
earth. It includes all the
land, air and water in
which organisms live.
Parts of the environment
• Abiotic factors- non- • Biotic factors- living
living parts of the
parts of the
environment.
environment.
• A-without, bio-life
• Ex: plants, animals
and other organisms.
• Ex: water, soil, light ,
temperature, wind, and
physical space.
1.43 Understand that and describe how organisms are influenced by
a particular combination of living and non-living components in the
environment.
Habitats
• Every species in a
habitat has
characteristics that
enable it to function in
the unique abiotic and
biotic factors.
• It provides the
members of a species
with food, shelter,
water, and whatever
else they need to
survive.
Species, Populations and
Communities
• Species are a group of
•
organisms so similar to one
another, they can breed and
produce fertile offspring.
• Populations are all of the
members of a single species •
that live in one area.
• Populations of different
organisms share a living space
and interact with one another.
All of the populations
that live and interact in
one environment make
up the community.
Can you give an
example of a species,
population and
community where you
live?
The Ecosystem
• All of the populations
and abiotic factors in
an area make up the
ecosystem.
• It can be a large
(forest, ocean, desert)
or small area (garden,
pond.)
• Healthy ecosystems
are very diverse.
Let’s Review the Organization of
Life in Ecology
From smallest to biggest
1. Organisms- ecologists study behaviors.
2. Populations- ecologists study the effects of them on the
environment and growth rates.
3. Communities- study the effects on a community when new
species are added or removed.
4. Ecosystem- ecologists are concerned with the stability of
the ecosystem.
5. Biosphere- ecologists are concerned with all interactions.
Niches
• A niche is the full range
of physical and
biological conditions in
which an organisms lives
and the way in which the
organisms uses those
conditions.
•
•
•
•
What organism eats
how it eats, where lives
how reproduces
temperatures needed to
survive
• where in food chain,
• An organism’s role in the Can two species share a niche in
the same habitat? Note:
environment.
different tree elevations may
be different habitats.
Community Interactions
• Competition occurs
when organisms of the
same or different
species attempt to use
an ecological resource
in the same place at
same time.
• Resource is any
necessity of life, such
as water, nutrients,
light, food or space.
• Competition
exclusion principle
states that no two
species can occupy the
same niche in the
same habitat at the
same time.
Resource Partitioning
• Some organisms use the same resource as others: fruit,
nuts, fish, light, water, minerals, etc.
• However, they may share if they use them at different
times or in different ways.
• Resource partitioning is a subdividing of some category of
similar resources that lets competing species coexist.
• Ex. Roots of plants in field. All use same resources, but
have different roots systems so they all can share. Pg. 709
Interdependence
•Organisms rely on their changing environment to survive.
How? Even a small change to one type of organism can have a
major impact on all of the other organisms in an environment.
Predator-prey relationships. (Co-evolution)
•Symbiosis- different species rely on each other. 3 kinds.
–Mutualism- both partners benefit.
–Commensalism- one partner benefits and the other is
unaffected.
–Parasitism- One benefits the other is harmed. Which
benefits? (40.6)
Give examples of each.
Parasite-Host Interactions
• Only 2 types of interactions kill a host
– Attacks a host with no coevolved defense against it.
– Host all ready has too many parasites on it.
Parasitoids- 15% of all insects. They develop inside
another species of insects, and devours from the inside as
they mature. They don’t always kill their host.
Larra Wasp, Ormia flies
Social Parasites
• Animals that take advantage of the social
behavior of a host species in order to carry
out their life cycle.
• Cowbirds lay eggs in another nest and the
bird feed them.
Adaptations of Prey
• What are some adaptations prey have to
survive?
• Camouflaging, warning coloration, mimicry
Adaptive Responses of Predators
What are some ways that predators counter prey
defenses with their own adaptations?
Stealth (out run), camouflage (wait on them),
‘ingenious” ways
Ex: Grasshopper mouse takes the edible beetle that
sprays chemicals at their predators through its end,
and puts the beetles end into the ground so it can’t
spray the mouse.
Changes in an Ecosystem
• Ecosystems can be reasonable stable over
hundreds of years. If a disaster such as a flood
or fire occurs, the damaged ecosystem is likely
to recover in stages that eventually result in a
system similar to the original one.
1.39
Changing with the Environment
• Ecosystems can be
• Ecosystems are always
relatively stable over
changing, sometimes quickly
hundreds or thousands
and dramatically with a fire or
of years.
flood or sometime slowly.
• Changing conditions
• Damaged ecosystems from a
affect the communities
flood or fire are likely to
recover in stages that eventually of organisms that live
results in a system similar to the in the ecosystem
original one.
1.39
Succession: Changes over Time
• Primary succession is the
• Orderly, natural
changes that take place colonization of new sites
by communities of
in communities of an
organisms after a change
ecosystem is a
in the ecosystem.
succession.
(Volcanoes)
• 1000’s of years
• What is a pioneer
• After time, primary
species?
succession slows down,
and the community
becomes fairly stable.
Secondary Succession
• Secondary succession is
the sequence of
• A stable, mature
community changes
community that
undergoes little or no
when a community is
succession, is a climax
disrupted by natural
community.
disasters or human
actions.
• Describe a place
• Fewer than 100 years
around you where you
have seen succession
occurring.
1.39
Succession in a Marine Ecosystem
• Note:
Succession
can happen in
any
ecosystem.
• The
following the
succession of
a whale-fall
community.
• Large whale dies and sinks to
ocean floor and attracts scavengers
and decomposers.
• Tissues are eaten by smaller org.
Decomposition enriches sediments,
for other species.
• Heterotrophic bacteria decompose
oil in bones and serve as energy
sources for chemosynthetic
autotrophs that support other org.
• Pg. 96
Cowbird Chutzpah
• Cowbirds originally evolved as
commenaslists with bison (ate insects as
kicked up) and as social parasites of other
bird species in the North Amercian Great
Plains. When conditions changed, the
expanded their ranged and now hold
“power” in woodlands as well as grasslands
of much of the US. They parasitize 15
species of native N. A. birds today.
Community Instability
• Keystone species- dominant species that can
dictate community structure.
Geographic dispersal
1. slowly expanding into hospitable regions
around home
2. Be transported (ships)
3. population moves out from its home range over
geological time.
Invasive Species
• In 1988, small
freshwater zebra
mussels were
introduced to Lake
Erie from Europe.
• They spread to all
great lakes in less than
10 years.
• They compete with
other species for food.
• They clog up waterintake pipes and farmirrigation pipes.
• One benefit- filterfeeding action h as
made water cleaner.
• Gypsy moths
1.38
Non-invasive
• Some species introduced are beneficial:
soybeans, rice, wheat, corn and potatoes
Plants That Ate Georgia!
• 1876 Kudzu was introduced from Japan to the
U.S.
• In Asia it was well behaved.
• Kudzu grows up to 60 meters a year.
• Asians use a starch found in the Kudzu for
drinks, herbal medicines, and candy.
• 90% of wallpaper in Asia is made from Kudzu.
• Goats and herbicides help to maintain it.
•
Sarah, Alli,
Alga!
• Was used in salt-water aquariums.
• Imported from Germany.
• Has covered more than 30,000 hectares of
sea floor along the Mediterranean Coast.
• It is now illegal to import alga.
• Some come into the U.S. with aquatic
trade.
Attack of the Bunnies!
• In the 1800’s, British settlers couldn’t
bond with Australia’s natural critters so
they brought some bunnies.
• It first happened in 1859.
• 6 yrs later a landowner killed 20,000
bunnies.
• There are 200-300 million bunnies in
Australia now.
Cont….
• In 1952, the government introduced the
myxoma virus that effect the South
American rabbits.
• The European rabbits were also effected.
• In 1991 researchers released rabbits that
had been injected with calicivirus.
• The rabbits died from clots in their lungs,
heart, and kidneys.
• In 1995 the virus spread killing 80-95 %
of adult bunnies in Australia.
• In 1996 it spread to other places.
The sum of all species occupying a specified
area during a specified interval, past as well
as present
A given area is an outcome of the evolutionary history of each member species and its
resource requirements, its physiology, and its capacity for dispersal.
Rates of Births, Death, Immigration, and Emigration
Habitat conditions and Interactions among species
Patterns have been discovered in biodiversity. They correspond to differences in the
habitat
The number of species is greater in the tropics and lessens systematically towards the
Poles
Than here
More here
Tropical latitudes get more sunlight, rainfall, and have a longer growing season. All of
which makes resource availability greater.
Tropical communities have been evolving longer than temperate ones
Species diversity might be self reinforcing
Meaning
More trees can exist at the lower altitude. More plant species compete and coexist. This
means more herbivores can C and C because a greater diversity of food is available.
(i.e. herbivores that survive on different plants can now live there) More predators can
then C and C because a greater diversity of food is available. Etc.
Tropical, equator places have more species than we would. We have more than the
North Pole.
Islands are good land masses to study
in biodiversity.
But the number of species will not
increase forever.
The further an island from a source of colonizing species, the less species diversity.
The Area Effect
The larger the area for species to live, the more diversity. Why?
Happens more on smaller islands. The small populations are more vulnerable to severe
storms, droughts, disease, and genetic drift.
Larger islands equals more
species
Threats to Biodiversity
• 300 mammals on extinction list
• Habitat loss due to physical reduction of suitable
places to live and chemical pollution
• Equilibrium model of island biogeography says
that 50% loss of habitat will drive about 10 % of
its endemic (specific to region, not introduced)
species to extinction.
• Indicator species
• Overharvesting, overfishing- bad.
Sustaining Biodiversity
• Hot spots- habitats with the greatest number of
species found nowhere else are in danger of
extinction.
• Ecoregion- Broad land or ocean defined by
climate, geography and producer species.
Reservoirs of biodiversity.
• Protecting biodiversity
– Strip logging- tropical slopes. Cleared in strips (fig.
40.30)
– Riparian zones (along rivers or streams). Provide
vegitation and line of defense against flooding. Restrict
or rotate cattle to prevent ruining the vegitation(fig.
40.31)
How Organisms Interact: Feeding
Relationships
Autotrophs- use energy
from the sun or stored
energy to make their
own food. They are
also called producers.
All organisms rely on
autotrophs for food.
Ex: plants.
• Heterotrophs- depend
on autotrophs and
their source of
nutrients and energy.
They are also known
as consumers.
• They include animals.
Photosynthesis vs. Chemosynthesis
• Photosynthesis- uses
light to make food
6CO2 + 6H20 
C6H12O6 + 6O2
• Chemosynthesis
• Hydrogen sulfide and
oxygen combine to form
sulfur compounds. Using
chemical energy, cells
make carbohydrates using
CO2 from sea water.
• Where are these bacteria
found?
Autotrophs
• Get their energy from the • Chemosynthesis is
sun through
when organisms use
photosynthesis.
chemical energy to
produce carbohydrates
• Use light energy to
when there is no light
power chemical reactions
present.
that convert carbon
dioxide and water into
• Bacteria- vents at
oxygen and sugar.
bottom of ocean is an
example.
• 6CO2 + 6H2O 
C6H12O6 + 6O2
Photosynthesis vs. Cellular
Respiration
• Photosynthesis
Captures energy
Chloroplasts
• Cellular Respiration
Releases energy
Mitochondria
• 6CO2 + 6H2O 
C6H12O6 + 6O2
• C6H12O6 + 6O2 
6CO2 + 6H2O
1.3, 1.4, 1.9, 1.43
Heterotrophs:
Carnivores and Scavengers
• Carnivores eat only
“meat”.
• What are some
examples of
carnivores?
• Scavengers eat
animals that are
already dead, they
don’t kill for food.
• What are some
examples?
• Why are they
important?
Herbivores
• Eat Plants
Omnivores and Decomposers
• Omnivores eat both
plants and animals.
• What are some
examples?
• Decomposers are
organisms that break
down and absorb
nutrients from dead
organisms.
• Ex: bacteria, some
protozoans, fungi.
• Why are they
important?
Detritivores
• Feed on plant and animal remains and other
dead matter called detritis
• Earthworms, crabs, mites, snails
Matter and Energy in Ecosystems
• When you pick an apple from a
tree and eat it, you are
consuming C, N and other
elements, and well as energy.
• Matter and energy are
constantly cycling through the
ecosystems.
• Conservation of mass and
energy laws: can’t be created
or destroyed. They are
transformed into different
forms.
Food Chain
• It is a simple model that scientists use to show how
matter and energy move through an ecosystem.
• Nutrients and energy flow from autotroph to
heterotroph to decomposers.
• They consist of 3 links, but no more than 5 because
the amount of energy by the 5th link is only a small
portion. Energy is lost as heat at each link.
• Ex: Algae Fish Bird
Trophic levels
• Each organism in a
food chain represents
a feeding step, or
trophic level, in the
passage of energy and
materials.
• They are many
“routes”.
• 1st level- photosynthetic
autotrophs- (producers.)
• 2nd level- first order consumers
(herbivores/omnivore)
• 3rd level- second order
consumers (carnivores.)
• 4th level- third order consumers
(carnivores that feed on second
order carnivores)
1.44 Describe the flow of energy within ecosystems.
Food Webs
• Food Webs
represent a
network on
interconnected
food chains.
• They express all
the possible
feeding
relationships at
each trophic
level in a
community.
DDT in Food Webs
• Biological Magnification- a substance degrades slowly or
not at all and becomes more concentrated in consumer
tissues as it moves to higher trophic levels
– DDtTis a synthetic pesticide that is mostly insoluable in water,
found anywhere.
– Wind carries the vapor and water moves it.
– Highly soluable in fats, and accumulates in animals tissue.
What it does?
disrupts physiology.
It is now banned thands to Rachel Carson who began the studies of
pesiticides.
Animals it has had a major effect on: pelicans, bald eagles and other
birds.
Nutrient Limitation
• Primary productivity
is the rate at which
organic matter is
created by producers.
• Controlled by amount
of available nutrients.
• When an organism is
limited by a single
nutrient that is scarce
or cycles slowly, the
substance is a limited
nutrient.
• Why would this be
important to
ecologists?
Algal Bloom
• If there is too much of a limiting nutrient (ie.
Fertilizer from field) that flows into water, this can
cause an immediate increase in the amount of
algae and other producers called an algal bloom.
• Why do they occur?
• This increases the number of producers, and
disrupt the ecosystem, if not enough consumers.
• Eutrophication- too much algae, takes up all of
the oxygen things die
Ecological Pyramids- show the relative
amounts of energy or matter contained
within each trophic level.
• Energy Pyramid- • Biomass Pyramid- shows
total amount of living
only 10% of the
tissue within a given
energy available
trophic level.
within one trophic
level is transferred • Pyramid of Numbersto organisms at the
shows relative numbers of
next.
individual organisms at
each trophic level.
Energy Pyramids
• To construct an energy pyramid for a
freshwater spring, you must measure the
energy transfers in each organism and then
multiply this by the population size.
Which pyramid is shown?
Some pyramids of energy use numbers to represent the number of
animals/plants there are for each level. If you had a tree that fed 50,000
insects, what would the pyramid look like?
Others use grams.
Cycling Maintains Homeostasis
• Energy is lost as heat to
the environment by body
processes at each level. It
flows one way.
• Sunlight is the source of
all energy.
• Matter also moves through
the trophic levels, but can’t
be replinished like
sunlight. Recycled
• Matter is constantly
recycled.
• Biological systems do
not use up matter, they
transform it into living
tissue, or passed out as
waste.
1.44 Describe the flow of matter and nutrients within ecosystems.
Why do we need the following?
•
•
•
•
Water
Carbon
Nitrogen
Phosphorus
What is the water crisis?
• Agriculture, drinking water, others?
• Water- liquid or solid on Earth and gas in the atmosphere.
The water cycle
• Evaporation of water from water bodies, animals and
plants.(liquid to gas)
• Condensation- gas to liquid in form of precipitation.
• Transpiration- loss of water vapor from plants.
• Respiration- gaseous exchange of oxygen and carbon
dioxide between organisms and environment. (Organisms
also lose water through excretion.)
• After an organism dies, decomposition releases water
back into the environment.
The Carbon Cycle
Carbon Cycle
• Carbon is found in the environment in the form of CO2
in the atmosphere and ocean.
• From the atmosphere, CO2 moves to aquatic and
terrestrial producers.
• Producers use CO2 in photosynthesis to make sugar, a
higher energy form.
• Organisms eat C when they consume “plants”.
• Respiration returns C to atmosphere in form of CO2 and
decay returns C to the environment.
• If decay occurs without O, the C can be bound up in a
fossil fuels that are burned and returned to the
atmosphere.
Fossil Fuels Formation
• Fossil fuels are made when plants and other organic
organisms die and decompose in the ground. Layers upon
layers are formed over many years. Through chemical
processes and pressure, fossil fuels are made.
• 1.42 Sometimes, the environmental conditions are such that
plants and marine organisms grow faster than decomposers
can recycle them back to the environment. Layers of energy
rich organic material thus laid down have gradually been
turned into great coal beds and oil pools by the pressure of
the overlying earth. Burning these fossil fuels, people are
passing most of the stored energy back into the environment
as had and release large amounts of CO2.
Terms
• Ammonification- bacteria and fungi break down
nitrogenous materials, forming ammonium
(NH3+) and either use it or return it to the soil.
Plants take it up.
• Nitrification- bacteria turn ammonium into nitrite
(NO2-) or nitrate (NO3-) by taking away
electrons.
• Dentitrificaiton- bacteria take nitrate or nitrite and
turn it into nitrous oxide (gas). Ananerobic.
Nitrogen Cycle
• Atmospheric N2 makes up nearly 78% of air.
• Living things can’t use N in atmospheric form.
• Lightning and some bacteria convert atmospheric N2 into
usable N-containing compounds. (nitrogen-fixing bacteria)
• Plants take up nitrates made from bacteria and lightning and
convert them into N-compounds.
• Herbivores eat the plants and convert N-plant proteins into
N animal proteins.During digestion, plant and animal
proteins are made into human proteins.
• Organisms return N to the atmosphere when they die and
decay.(denitrification)
• Fertilizers from farming are taken up by plants or runoff
into body of waters.
Nitrogen Cycle
Phosphorus Cycle
Phosphorus Cycle
• Plants use P from the soil in their body tissues.
• Animals get P by eating plants.
• When the animals die, they decompose and the P is
returned to the soil to be used again. (Short-term cycle.)
• Phosphate washed into the sea become incorporated into
rock as insoluable compounds. Millions of years later, as
the environment changes, the rock is exposed and made
part of the ecological system. (long-term cycle.)
Greenhouse Effect- trapping of heat
in the atmosphere
• CO2, methane water
vapor and a few other
atmospheric greenhouse
gases trap heat energy
and maintain Earth’s
temperature range.
• Greenhouse effect is the
natural situation in
which heat is retained by
the layer of greenhouse
gases.
Ozone Layer
• Band of ozone (O3) that
shields the earth from
much of the sun’s harmful
UV radiation.
• Thining increases the
exposure to UV radiation,
increasing cataracts and
skin cancer and reduce
crop supply. It may
decrease resistance to
disease.
• Causes of thining:
– CFC’s (chloroflorocarbons
are ordorless, noncorrosive
compounds that were once
used as proprellants in
aerosol cans and in
production of plastic foam,
coolants in air conditions,
refrigerators and freezers.
Global Warming
• Global warming is is the
increase in the Earth’s
average temperature.
• Much of the sunlight that
hits the surface of our planet
is converted into heat energy
and then radiated back into
the atmosphere.
• Greenhouse gases do not allow
heat E to pass out of the
atmosphere as readily as light
energy enters it.
• The gases trap the heat.
• If these gases were not present
in the atmosphere, the Earth
would be 30oC cooler.
• Where are some of the gases • In 2050, Earth’s temp may
coming from that are causing
increase by 2 to 4oC.
this effect?
Weather and Climate
• Weather is the dayto-day condition of the
Earth’s atmosphere at
a particular time and
place.
• Climate is the typical
weather pattern over
time in an area. (avg.
year around
temperature)
• Ecosystems can
change with climate
changes. Hot, cold,
rainy, sunny. (1.40b)
• Can you think of any
examples where
ecosystems have
changed with the
environment?
Latitude and Longitude
• Longitude – vertical
• Latitude- horizontal
• Polar, Temperate and
Tropical.
• As a result of
differences in latitudes
and thus the angle of
heating, Earth has 3
main climate zones.
• Where do you think
each are located?
Climate Zones
• Tropical Zoneequator to 30o N and
30oS latitudes.
• Temperate Zone- 30o
to 60o N and S
latitudes.
• Arctic (Polar)Zonebeyond 60o N or S
latitudes.
Heat Transport in the Biosphere by
Winds
• The unequal heating of the Earth’s surface
drives winds and ocean currents, which
transport heat throughout the biosphere.
• Winds form because warm air rises and cool
air sinks. What zones does air rise? Sink?
• Prevailing winds bring warm or cold air to a
region, affecting it’s climate.
Ocean currents
• Cold water sinks, warm water rises.
• Cold water near the poles sinks and then
flows parallel to the ocean bottom,
eventually rising again in warmer regions in
a process called upwelling.
• Surface water is moved by winds.
Why do you think the westerlies move east and easterlies move
• A biome is a large group of
ecosystems that share the
same type of climate
community.
• Land- Terrestrial
• Water- Aquatic
• Microclimate- climate in a
small area that differs from
the climate around it.
• Fog
(Make graphic organizer for
biomes including: climate, flora,
fauna, location, other
characteristics.
Biomes
Biome link
Climatogram
• Shows two components of climate
• Temperature and precipitation
San Luis Opispo,
California
Biomes are determined by climates
(temperature and precipitation).
Tundra
• Tundra: cold and treeless, and most of the soil is
permanently frozen. A thin layer of soil thaws
briefly during short, cool, summers. Winters are
long, dark and very cold.
• plant life in the tundra consists of mosses and
lichens
• Where do you think tundras are located?
• Artic Zone
• Northern N. America, Asia, Europe
Taiga (Boreal Forest)
• Taiga: located south of the tundra, at the
northern edge of the temperate zone.
Winters are long, cold, and summers are
relatively mild.
• How are they different from tundras?
• The taiga climate and soil can support trees
such as conifers;.
• N America, Asia, and N. Europe
Temperate Forest
• Grows where summers are pleasantly warm with
frequent rains, and winters are somewhat cold.
• What type of trees make up a temperate forest?
• Tall deciduous trees and coniferous trees.
– Conifers- seed-bearing cones and needles.
– Deciduous-sheds leaves during particular season.
Eastern US, SE Canada, most of Europe, parts of Japan,
China and Australia
Chapparral (Temperate Woodland
and Shrubland)
• Warm region that has a rainy winter season,
followed by a long, dry summer.
• How do chapperal organisms adapt to these
extremes in precipitation?
• Plants are drought-resistant; reptiles and
insects have thick, watertight coverings.
• W coasts of N and S America,
Mediterranean Sea, S. Africa, Australia
Tropical Rain Forest
• Warm, wet weather, lush plant life, and diverse
animal life. Poor soil
• What abiotic factors contribute to this diversity?
• Sunlight, water, soil and temperature.
• Parts of S. and Central America, SE Asia, parts of
Africa, S India, NE Australia
• Tropical Dry Forests – rainfall is seasonal rather
than year round. Rich Soil
• Parts of Africa, S. and Central America, Mexico,
India, Australia and Tropical Islands
Desert
• Too little precipitation creates deserts, arid regions
with sparse plant life.
• Extremely dry, hot deserts may consist only of
shifting sand dunes. Deserts: Africa, Asia, Middle
East, US, Mexico, S. America, Australia
• Extremely cold deserts include those is in
Mongolia and China.
• How do plants conserve water?
• Store water in thick, succulent stems.
Grassland
• Widespread communities characterized by grasses
and small plants.
• Temperate grasslands( summers hot and winters
are cold and windy)
– Central Asia, N. America, Australia, central Europe,
upland plateaus of S. America
• Tropical savannas (warm year-round and have
alternating wet and dry seasons.)
– Large parts of eastern Africa, southern Brazil, northern
Australia
Other Land Areas
• Mountain ranges- abiotic
and biotic conditions vary
with elevation.
• Move up temperature
decreases and
precipitation increases.
• Polar ice caps- cold year
round.
• Mosses and lichens grow.
• Few plants
• Northern- Polar bears,
seals, insects and mites.
• Southern polar region5km of ice. Penguins and
marine animals.
Marine Biomes
• Most of the water on
earth is salty.
• Fresh water is
confined to rivers,
streams, ponds, and
most lakes.
• Photic Zone is the
portion of the marine
biome that is shallow
enough for sunlight to
penetrate.
• Aphotic Zone- Deeper
water that never
receives sunlight.
Water Biomes
Freshwater
3.
Wetlands: ecosystem where water either covers the soil or is present at or near the
surface of the soil for at least part of the year.
Bogs-freshwater wetlands
Marshes- shallow wetlands along rivers
Swamp- flooded forest
4. Estuary: wetlands where fresh water and saltwater mix. They form where rivers
meet the sea and deposit nutrient-rich sediment.
detritus- tiny pieces of organic material that are food.
Salt marshes- temperature zone estuaries dominated by low-tide line and seagrasses
underwater.
Coastal Wetlands (mangrove swamps): along seacoast that are sometimes mixed
with saltwater. Florida
Marine Zones
Phytoplankton and algae
Coastal OCEAN
Kelp forests
Bottom-dwellers, sea
stars, shrimp, crabs,
clams, worms,
urchins, sponges and
sea anemones.
Benthic Zone
Squids and
fishes make
their own
light.
Marine Ecosystems
• Intertidal Zone- org. exposed to regular and
extreme changes. Tides moves. Star fish
and clams must attach themsevles.
• Coastal Ocean- extends from low-tide mark
to the outer edge of the continental shelf.
– Kelp forests
– Coral Reefs- calcium carbonate
Marine Ecosystems
• Open ocean- 500 m to 11,000 m. Low
levels of nutrients. Octopods, dolphins,
whales, fish.
• Benthic Zone- ocean floor. Cold, dark,
pressure at bottom
Biosphere Review
• Click on the following link and choose your
text book. Review the links and take the
self-test.
• Ch. 3 Review
Characteristics of Populations
1. Geographic
distribution
2. Population density
3. Growth rate
Population Size
•
Affected by:
1. Number of births
2. Number of deaths
3. Number of
individuals that enter
or leave a population.
( immigration vs.
emmigration)
Affecting Other Populations
• Factors that limit one
population in a
community may also
have an indirect effect
on another population.
• Ex: lack of water
affects the growth of
grass, reducing the
number of seeds
produced. The mice
population have less
food, the hawks have
less food, and so on.
Exponential Growth
• Exponential growth
• Bacteria growth: let’s
occurs when the rate
look at it.
of a population growth
in each new generation • Will you work for
is a multiple of the
pennies? Activity.
previous generation.
Growth rate = change in number of individuals
Time period
Logistic Growth
• As resources become
less available, the
growth of a population
slows or stops.
• Logistic growth occurs
when a population’s
growth slows or stops
following a period of
exponential growth.
Tutorial
Exponential Growth Meets the
Real World
• Limiting factor is any
biotic or abiotic
resource in the
environment that
limits the size of a
population.
• Carrying capacity is
the number of
individuals in a
population that an
environment can
support over a long
period of time.
Limiting Factors
• Environmental factors
such as food
availability and
temperature that affect
an organism’s ability
to survive in its
environment are
limiting factors.
• Limiting factors can
be biotic or abiotic
factor that restricts the
existence, numbers,
reproduction, or
distribution of
organisms.
Limits on Population Growth
• Limiting factors
either cause a
decrease in birth rate
or an increase in the
death rate.
Density-Dependent limiting
factors
• Factors become
limiting only when the
population density (#
of org. per unit space),
reaches a certain level.
• Gypsy moths and
zebra mussels
• Ex:
– Predation
• Increase predatorsdecrease prey
– Disease
• More dense populationlimited growth
– Competition
• Competing for
resources
Density- Independent Limiting
Factors
• Factors that affect all
populations in the
same way, regardless
of density.
• Ex:
–
–
–
–
Weather
Seasonal Cycles
Natural Disasters
Human Activities
Human Population Growth
• Human population
was very slow for
thousands of years.
• Between 1650 and
1850 the population
doubled, passing the 1
billion mark.
• After 1850, it only took 80
years to double to 2
billion.
• 4 billion 45 years later.
• It is estimated that the
human population in now
increasing 90 million
people a YEAR.
• Far more people are born
than are dying. 3x as
many.
Patterns of Population Growth
• Demographic
Transition- dramatic
change in birth and
death rates.
• What do you think the
trend is now with birth
and death rates?
• Age-structure
diagrams- graph
number of people in
different age groups in
the population.
• What event is shown
in the next agestructure diagram?
What is the future like for
population growth?